Company lists · Data refreshed September 2026

Top 25 Investigation firms based in Chicago, United States

Name: Investigation firms based in Chicago, United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 20, 2026 65 companies tracked

RevenueBase identified 65 investigation firms headquartered in Chicago, United States as of September 2026 and tracks 948 professional contacts across them, including 423 with verified work emails. New York is the largest hub.

This list covers investigation firms headquartered in Chicago, United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 20, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 20, 2026 86% judged on-target in blind review

65Companies

948Contacts tracked

423Verified emails

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The 25 largest investigation firms based in Chicago, United States

Ranked by team size

Top 25 of 65 investigation firms based in Chicago, United States, ranked by team size, largest first. Data refreshed Sep 20, 2026. RevenueBase Smart Search rates how each company's information relates to investigation firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Envista Forensics	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	201-500	376 contacts →
	Indirect evidence “Envista Forensics is the global leader in providing comprehensive forensic consulting and engineering services.” Source: RevenueBase Database · checked Sep 20, 2026
2	Prescient	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	51-200	52 contacts →
	Indirect evidence “Prescient helps multinational corporations, law firms, investors, and private clients mitigate risk and discover actionable intelligence using next generation technology and…” Source: RevenueBase Database · checked Sep 20, 2026
3	Novus LAW LLC	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	51-200	33 contacts →
	Strong evidence “Novus Law is a global legal services firm that finds The Story of 'what happened' in all types and sizes of disputes and investigations.” Source: RevenueBase Database · checked Sep 20, 2026
4	Arms Security Corporation	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	501-1,000	27 contacts →
	Strong evidence “Trusted protection and investigative services with a commitment to excellence.” Source: RevenueBase Database · checked Sep 20, 2026
5	Elijah	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	21 contacts →
	Indirect evidence “ELIJAH is a premier provider of digital forensics, eDiscovery, data security, and technology services.” Source: RevenueBase Database · checked Sep 20, 2026
6	Sigma7 RWH Myers	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	12 contacts →
	Indirect evidence “RWH Myers is a forensic accounting firm with one goal: your peace of mind.” Source: RevenueBase Database · checked Sep 20, 2026
7	Inner Valor, INC	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	201-500	12 contacts →
	Strong evidence “Inner Valor is a premier provider of White Glove Security℠ and corporate investigation services, offering elite and personalized solutions to protect your assets, people, and…” Source: RevenueBase Database · checked Sep 20, 2026
8	Boomerang Information Services, INC	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	11 contacts →
	Indirect evidence “Boomerang Information Services is a trusted partner for public records research, document retrieval, and filing services.” Source: RevenueBase Database · checked Sep 20, 2026
9	Mccarthy Byrnes	Strong evidence	Chicago, United StatesHQ checked Sep 20, 2026	11-50	10 contacts →
	Strong evidence “Security Consulting \| Private Investigations \| Law Enforcement Consulting \| McCarthy Byrnes is a trusted security, investigations, and public safety advisory firm providing…” Source: RevenueBase Database · checked Sep 20, 2026
10	It's Your Serve	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	9 contacts →
	Indirect evidence “It's Your Serve is a licensed private detective agency providing process service and skip tracing to lawyers nationwide” Source: RevenueBase Database · checked Sep 20, 2026
11	221b Partners	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	7 contacts →
	Strong evidence “Founded by professionals with decades of diverse experience conducting complex multi-jurisdictional investigations, 221B Partners finds the dots and connects them.” Source: RevenueBase Database · checked Sep 20, 2026
12	Axium Consulting	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	7 contacts →
	Indirect evidence “Axium assists clients worldwide in understanding risks and making informed decisions.” Source: RevenueBase Database · checked Sep 20, 2026
13	Redhawk Investigations & Security	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	6 contacts →
	Strong evidence “RedHawk is a Investigations and Security Risk Management firm specializing in comprehensive, professional and discreet services to a wide variety of US based and international…” Source: RevenueBase Database · checked Sep 20, 2026
14	Greene Forensic Accounting Solutions LLP	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	6 contacts →
	Indirect evidence “Greene Forensic Accounting Solutions LLP is a forensic accounting and consulting practice with offices in the Chicago and Las Vegas areas, allowing us to provide our clients with…” Source: RevenueBase Database · checked Sep 20, 2026
15	Troy Group, INC	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	6 contacts →
	Strong evidence “Headquartered in Chicago and established in 1998, Troy Group provides investigative services specializing in due diligence investigations.” Source: RevenueBase Database · checked Sep 20, 2026
16	Lewitas Hyman PC	Indirect evidence	Chicago, United StatesHQ checked Sep 20, 2026	1-10	5 contacts →
	Indirect evidence “Lewitas Hyman PC (now known as Hyman Cotter PC) provided nationwide advisory and litigation counsel to clients in the financial services industry on employment and investment loss…” Source: RevenueBase Database · checked Sep 20, 2026
17	Protek International	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	5 contacts →
	Strong evidence “Protek provides a unique perspective to address the many facets of technology and digital evidence, investigations, enterprise risk and litigation.” Source: RevenueBase Database · checked Sep 20, 2026
18	Teamwerks	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	5 contacts →
	Indirect evidence “TeamWerks is an IT company based in the United States.” Source: RevenueBase Database · checked Sep 20, 2026
19	Ablin LAW PC Workplace Investigations	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	4 contacts →
	Strong evidence “Ablin Law specializes in providing employers and law firms with expert, professional and confidential workplace investigation solutions.” Source: RevenueBase Database · checked Sep 20, 2026
20	Gould & Pakter Associates, LLC	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	4 contacts →
	Strong evidence “G&P is a certified public accounting firm that, among other services, provides financial forensics, commercial litigation services, internal investigations and financial analysis…” Source: RevenueBase Database · checked Sep 20, 2026
21	AM Legal Services, INC	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	4 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026
22	TOP Tier Safety INC	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	11-50	4 contacts →
	Strong evidence “Top Tier Safety Inc is a security and investigations company based out of E Wacker, Chicago, Illinois, United States.” Source: RevenueBase Database · checked Sep 20, 2026
23	On Q Professional Investigations	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	3 contacts →
	Strong evidence “On Q Professional Investigations (ONQPI) is a licensed Illinois Private Detective Agency, founded by former United States Department of Homeland Security-ICE Agent, Tony Quintana.” Source: RevenueBase Database · checked Sep 20, 2026
24	RGH Investigations	Strong evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	3 contacts →
	Strong evidence “Private investigator Chicago, Robert G Hanrahan, RGH Investigations is a licensed Chicago private detective specializing in process server, surveillance, locates, automotive…” Source: RevenueBase Database · checked Sep 20, 2026
25	Optis Partners, LLC	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 20, 2026	1-10	2 contacts →
	Indirect evidence “OPTIS Partners is an investment banking and consulting firm based in Chicago, IL made up of a small group of highly skilled insurance and finance professionals with extensive…” Source: RevenueBase Database · checked Sep 20, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: investigation firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names investigation firms.
Partial evidence: Its own public description names part of investigation firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name investigation firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 65 investigation firms based in Chicago, United States

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Investigation firms based in Chicago, United States at a glance

As of Sep 20, 2026

44.6%Verified-email coverage

14.6Average contacts per company

1-10Median size (employees)

223.1%Largest-city concentration · New York

Sep 20, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

Email recency for this list is measured across the whole United States list rather than for Chicago, so it is reported there. Company counts and contact totals on this page are exact for Chicago, over 65 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among investigation firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in Chicago, United States whose own description of what they do matches “investigation firms”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names investigation firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among investigation firms, and records with no verified work email. Companies headquartered outside Chicago are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 423 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 20, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Investigation firms by metro in the United States

Investigation firms in New York145
Investigation firms in Houston74
Investigation firms in Chicago65
Investigation firms in Los Angeles61
Investigation firms in Miami60
Investigation firms in Washington48
Investigation firms in Dallas46
Investigation firms in Atlanta45
Investigation firms in Phoenix37
Investigation firms in Denver34
Investigation firms in Fort Lauderdale31
Investigation firms in Tampa31
Investigation firms in Boston29
Investigation firms in San Diego29
Investigation firms in Seattle29
Investigation firms in Orlando28
Investigation firms in Las Vegas27
Investigation firms in Austin25
Investigation firms in Nashville25

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names investigation firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many investigation firms are there based in Chicago, United States?

RevenueBase identified 65 investigation firms headquartered in Chicago, United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Envista Forensics, headquartered in Chicago, tops this list with the largest team on record.

Which city has the most investigation firms?

New York leads with 145 headquartered companies, followed by Houston (74) and Chicago (65).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 423 verified decision-maker contacts tracked across these 65 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 20, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.